Sudden oil loss-Yanmar

[Stu Jackson]

wings, you may not be aware of this, but sailorchic tore down and rebuilt here engine in her cockpit last year.

Believe her, she knows what she's talking about.

Follow her suggestions.

[marlinmike]

The OP said he took out/bypassed the oil cooler and it still used oil. Valve stems traditionally do not dump that level of oil, more often when shut down oil would leak down into the cyl and at start up head smoke until it cleared.

[sailorchic34]

Originally Posted by marlinmike

The OP said he took out/bypassed the oil cooler and it still used oil. Valve stems traditionally do not dump that level of oil, more often when shut down oil would leak down into the cyl and at start up head smoke until it cleared.

I think he said he removed the coolant hoses and did not see any oil in the coolant side of the heat exchanger. But I bet the engine was cold when he tested it too. Maybe only a few minute run.

Agree that is not really valve stems not at a quart per hour.

Looking at how the oil cooler is plumbed on the 3JH oil filter, It appears as a side stream cooler, I expect the differential pressure across the filter causes the flow to the oil cooler. When cold the oil filter bypass opens and you have little differential pressure to push the oil to the cooler.

I'm still looking for a schematic of the 3JH oil circuit.

I don't see how you can loose a quart per hour on a engine otherwise. Not one without external leaks, starts easy and does not smoke. It just about has to be a leak in the pressurized oil lines.

EDIT: OK,the oil lines on the 3jh2e are NOT side stream but take full flow, least that is how it looks too me. There is a pressure bypass built into the housing that the oil filter and oil lines is mounted on.

I would completely bypass the oil cooler raw water lines and run the engine for a while, 1/2 to one hour just to verify that the oil cooler is not the problem. Put a raw around the ends of the raw water to see if any oil comes out. As long as your not running above 2200 rpm ish, there shouldn't be a problem disconnecting the oil cooler. It is connected to the raw water side.

[marlinmike]

I concurr 100% with sailorchic34, somewhere there is 4 qts of oil hiding!:

"I don't see how you can loose a quart per hour on a engine otherwise. Not one without external leaks, starts easy and does not smoke. It just about has to be a leak in the pressurized oil lines.

EDIT: OK,the oil lines on the 3jh2e are NOT side stream but take full flow, least that is how it looks too me. There is a pressure bypass built into the housing that the oil filter and oil lines is mounted on.

I would completely bypass the oil cooler raw water lines and run the engine for a while, 1/2 to one hour just to verify that the oil cooler is not the problem. Put a raw around the ends of the raw water to see if any oil comes out. As long as your not running above 2200 rpm ish, there shouldn't be a problem disconnecting the oil cooler. It is connected to the raw water side."

[wingssail]

Well, we've gotten to Puntarenas, two nice afternoons of sailing and a great anchorage in between. (Gotta look for the silver lining).

The mechanic agrees with you all and I guess I do too, and I'm hoping, because this is an easy fix. He'll pull off the oil cooler and take it to be pressure tested. In the meantime I'll probably run the 1 hour test suggested. My last test bypassing the oil cooler was just a few minutes.

BTW, today we motored up the river to the marina, dead slow due to the shallow water, and...No noticable oil loss in 1 hour.

We will update this forum when we get definitive answers.

[Cavalier]

Originally Posted by wingssail

We will update this forum when we get definitive answers.

Please do, always good for the benefit of the group to finish a thread with a definitive solution.

[Terra Nova]

Originally Posted by wingssail

... the engine alarm sounded (started chirping) and we saw low oil pressure and shut down the engine. The oil level did not show on the dipstick.

We put in two quarts which brought it up to nearly full and restarted the engine. Within 1 1/2 hours the oil was gone and the pressure low again...

Originally Posted by wingssail

...today we motored up the river to the marina, dead slow due to the shallow water, and...No noticable oil loss in 1 hour...

I can tell you what the problem is.

The oil level had not been checked in quite some time. When it finally got so low as to cause loss of oil pressure, OP added 2 quarts. On restarting the engine, oil was once more distributed inside the engine's oil passages. Subsequent dipstick reading showed the oil was down again.

The engine definitely did not burn 2 quarts in 1.5 hours. You're wasting $ on a mechanic.

[wingssail]

Originally Posted by Terra Nova

I can tell you what the problem is.
The engine definitely did not burn 2 quarts in 1.5 hours. You're wasting $ on a mechanic.

Well, Terra Nova, I really hope you are right

I am not trying to bore you guys, and I am not making any of this up, but here are the facts:

Between May 20th when the hour meter read 5443.0 and May 23rd when the hour meter read 5450.2, which represents 7.2 hours of operation, we added 8 quarts of oil. We found no sign of where it went, no smoke, none in the bilge, none apprecable in the exhaust water.

We are now at a dock, the hour meter reads 5453.2, and we have motored to the marina and have performed several further checks, and found no issues. However, the motoring and subsequent tests, adding the 3 additional hours of engine operation, show...NO FURTHER OIL LOSS! If anything, the dipstick might even be up a smidge.

Did anything get changed? Yes. The stbd tank fuel filter became plugged at around hour 5450.2 and we switched to the other tank. Today's test was conducted back on the starbord tank after replacing the filter.

Also, at hour 5450.7, during docking, when I gave the throddle a sharp jab, we had a puff of blue smoke, very untypical.

Today we ran for an hour and a half and collected about 40 gallons of exhaust water to examine for oil. Other than a slight sheen, the amount of which which we could not measure, there was no appreciable oil. Of course, during this period today, we also saw no oil loss.

So we are as baffled as ever.

Tomorrow we will pull the oil cooler and send to a shop for a pressure test and we will examine the fuel pump.

BTW, I very much appreciate all of your comments and thinking on this, and particularly Sailorchic. Your expertise clearly exceeds mine and where I am now, there are not too many folks around to bounce ideas off of.

[Tx J]

Have you checked the oil level in the transmission?

I have no idea how this engine and transmission are mated together, but if there is a more or less direct, sealed connection between them (w/bellhousing?), maybe a rear oil seal leak could be pumping oil into the tranny.
And if it were four quarts or more it may be getting "full" in there (I think most trans are only filled partially normally, and the gears splash it around). If so, running at high speed could develop enough pressure in there to really blow something.

I know I have a pdf manual for this engine in my library, but right now pulling up the pdf reader would probably crash my 'puter (got it overloaded ATM).
Still patching it up after recent power failure (lightning strikes took coml pwr out three times, last was for ~4 hours).
Storms took down and 'failed' my huge sxs Whirlpool icebox for 3-4 days too (at home), long enough to wipe out my food supply; now the dang thing is back working-- but without replacing it's relays, can't trust it again.

[sailorchic34]

Originally Posted by wingssail

Between May 20th when the hour meter read 5443.0 and May 23rd when the hour meter read 5450.2, which represents 7.2 hours of operation, we added 8 quarts of oil. We found no sign of where it went, no smoke, none in the bilge, none apprecable in the exhaust water.

We are now at a dock, the hour meter reads 5453.2, and we have motored to the marina and have performed several further checks, and found no issues. However, the motoring and subsequent tests, adding the 3 additional hours of engine operation, show...NO FURTHER OIL LOSS! If anything, the dipstick might even be up a smidge.

Did anything get changed? Yes. The stbd tank fuel filter became plugged at around hour 5450.2 and we switched to the other tank. Today's test was conducted back on the starbord tank after replacing the filter.

Also, at hour 5450.7, during docking, when I gave the throddle a sharp jab, we had a puff of blue smoke, very untypical.

Today we ran for an hour and a half and collected about 40 gallons of exhaust water to examine for oil. Other than a slight sheen, the amount of which which we could not measure, there was no appreciable oil. Of course, during this period today, we also saw no oil loss.

So we are as baffled as ever.

That is interesting and amazing.

With the above information, I can deduce something completely different. If the oil cooler comes back fine and I'm now betting that it does, then look to your fuel lift pump. I'm thinking your fuel lift pump has a tear in the diaphragm. With the tank filter mostly clogged, the tear in the fuel lift pump diaphragm might suck the oil out of the engine due to the high vacuum generated by the pump. Change the fuel filter and you have a low vacuum and now you'll get fuel in the oil.. That the oil level might be rising is also a clue that the diaphragm might be faulty. The blue smoke might be from the excess oil now in the starboard tank.

The lift pump is located on the side that the cam shaft is on, this is also the side with the oil galleys draining oil back to the sump from the head. I'm thinking oil that ran down the wall over the fuel pump lever may have been sucked out via a tear in the pump diaphragm caused by high vacuum from the dirty fuel filter.

[Terra Nova]

Originally Posted by sailorchic34

...That the oil level might be rising is also a clue that the diaphragm might be faulty...

That the oil level appears to be rising is more likely a clue of poor dip-stick technique.

Accurate comparisons can only be expected under similar conditions, like always checking the oil, cold, before starting. The level will likely be much different from checking immediately after shutting down a hot motor, or immediately after adding oil.

You can be assured the oil level is not suddenly rising.

[chouliha]

Good luck Fred!

[sailorchic34]

Originally Posted by Terra Nova

That the oil level appears to be rising is more likely a clue of poor dip-stick technique.

Accurate comparisons can only be expected under similar conditions, like always checking the oil, cold, before starting. The level will likely be much different from checking immediately after shutting down a hot motor, or immediately after adding oil.

You can be assured the oil level is not suddenly rising.

I'm sure your aware that a primary symptom of a bad Yanmar lift pump (well most engine driven lift pumps) is that fuel will leak into the oil causing the oil level to rise. It's quite common and not at all rare.

It would not be outside the realm of possibility for oil to be sucked into the pump under partial vacuum, caused by a mostly clogged fuel filter.

That the oil leak stopped after the fuel filter was replaced, we can apply a correlation between the two events.

As to the comment about the oil leaking past the rear seal. That is of course possible. But there are openings in the yanmar bell housing and the flywheel would be slinging oil out those holes with vigor. As there is no visible sign of an oil leak, it's probably not a rear seal.

[Terra Nova]

34--think Occam's Razor.

[sailorchic34]

Originally Posted by Terra Nova

34--think Occam's Razor.

Oddly I always do....

With an engine that has lost 2 gallons of oil over a very short run time with no external sign that now does not use oil after changing a fuel filter, what would you say the problem was??